A compound objective lens is composed of a hologram lens for transmitting a part of incident light without any diffraction to form a beam of transmitted light and diffracting a remaining part of the incident light to form a beam of first-order diffracted light, and an objective lens for converging the transmitted light to form a first converging spot on a front surface of a thin type of first information medium and converging the diffracted light to form a second converging spot on a front surface of a thick type of second information medium. Because the hologram lens selectively functions as a concave lens for the diffracted light, a curvature of the transmitted light differs from that of the diffracted light. Therefore, even though the first and second information mediums have different thicknesses, the transmitted light incident on a rear surface of the first information medium is converged on the its front surface, and the diffracted light incident on a rear surface of the second information medium is converged on the its front surface. That is, the compound objective lens has two focal points.

Compound objective lens having two focal points

An optical head apparatus consists of a semiconductor laser for radiating a light beam, a first collimator lens for collimating the light beam, a wedge-like prism for reshaping the light beam, a beam splitter for transmitting the light beam in an outgoing path and splitting the light beam in an incoming path, an objective lens for converging the light beam at an information medium in which information is stored, a plane type of hologram lens integrally formed with the objective lens for excessively correcting chromatic aberration of the objective lens to cancel out chromatic aberration of the collimator lens, a second collimator lens for converging the light beam split, a photo detector for detecting intensity of the light beam converged to obtain an information signal and servo signals, and an actuating unit for slightly moving the objective lens and the hologram lens according to the servo signals. A wavelength of the light beam is lengthened as intensity of the light beam is increased. Even though an astigmatic difference occurs in the semiconductor laser, the change of a focal length of the collimator lens cancels out the change of the astigmatic difference to prevent the occurrence of astigmatic aberration.

Optical head for adjusting a positional relation between the information medium and the optical head

The possibility and the efficiency of using a single diffractive lens to achromatize and apochromatize micro-objectives with plastic lenses are shown. In addition, recommendations are given on assembling the starting configurations of the objectives and calculating the design parameters required for subsequent optimization. It is also shown that achievable optical performance of achromatic and apochromatic micro-objectives with plastic lenses satisfy the qualifying standards for cell-phone objectives and closed-circuit television (CCTV) cameras.

Design of achromatic and apochromatic plastic micro-objectives

A method of designing a plastic zoom lens with a diffractive-refractive hybrid corrector, comprising one diffractive lens and one refractive lens, is described. The efficiency of this method is demonstrated by designing a compact zoom lens for a mobile phone. This zoom design, incorporating lenses made only of two commercial optical plastics (polymethylmethacrylate and polycarbonate), provides high optical performance.

Diffractive–refractive correction units for plastic compact zoom lenses

A multiview three-dimensional image display system comprises an image projection screen, two image generation components, a bifold mirror, an spatial light modulator, and projection optics. Each of the image generation components generates successive finite time sequences of time-multiplexed multiview images and thus form a channel of multiview images. Each of the reflecting surfaces of the bifold mirror reflects a different one of the two channels of multiview images. The spatial light modulator comprises a plurality of strip-like shutters, each of which transmits a different one of the finite time sequences of time-multiplexed multiview images. The projection optics projects the images through the spatial light modulator onto the image projection screen, where the spatial light modulator is imaged to make a single viewing zone.

Multiview three-dimensional image display system

A new version of the DEMOS program is presented DEMOS (design, evaluation, and modeling of optical systems) is integrated dialog software for automatic modeling to estimate and design optical systems with conventional and hologram optical elements The theoretical principles and the current state of the primary possibilities and application principles of the DEMOS program for optical systems design and simulation on computers are discussed

DEMOS : state-of-the-art application software for design, evaluation, and modeling of optical systems

The results of development of optical system with holographic optical elements (HOE) and the main possibilities of program complex DELOS for modelling and optimization of optical systems with HOE have been considered. Development methods of new classes of optical systems based on phase three-dimensional wide-angle HOE with a considerable remoteness of pupil and apochromats-anastigmats based on kinoform elements without use of special glasses or crystals are discussed. Analysis of aberration and correction possibilities of different types of HOE is given. Characteristic properties of HOE computation and modelling for control of aspherical mirrors have been considered.

Optical Systems With Holographic And Kinoform Elements

A new version of DEMOS program is presented. DEMOS (design, evaluation, and modeling of optical systems) is an integrated dialog system for modeling, evaluation, and design of optical systems with conventional and hologram optical elements (HOE). Theoretical principles and modern state-of-the-main possibilities and application principles of DEMOS program for optical systems with HOE design on personal computers are discussed.

Design of optical systems with HOE by DEMOS program

A near diffraction limited kinoform tele-apochromat-anastigmats was designed for broadband spectral range images. By use of kinoform elements, the apochromatic correction of the aberration is achieved without the load- dispersion glasses or crystals both for infinity and for the finite distance. Design and results of the testing are presented.

Apo-tele lenses with kinoform elements

Principles are discussed of numerical design and simulation of laser telescopes, using phase conjugation technique for compensation of the distortions, introduced by the primary mirror and some other elements. Described are the approaches to the dimensional and aberrational design, as well as numerical evaluation of the system compensational abilities. Several specific systems, in particular, the beam prototype for the space-based ecology monitoring LIDAR system, illustrate the principles discussed.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Mikhail A. Gan

Papers

DEMOS : state-of-the-art application software for design, evaluation, and modeling of optical systems

Optical Systems With Holographic And Kinoform Elements

Design of optical systems with HOE by DEMOS program

Apo-tele lenses with kinoform elements

Numerical design and modeling of the telescopic systems compensated via phase conjugation